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Add an option to guess the drop rate

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This commit is contained in:
Eric Fischer
2015-12-16 12:13:24 -08:00
parent eb906dfc72
commit 6681817243
3 changed files with 43 additions and 15 deletions
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geojson.c
+37 -11
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@@ -1046,7 +1046,7 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
exit(EXIT_FAILURE);
}
if (basezoom < 0) {
if (basezoom < 0 || droprate < 0) {
struct index *map = mmap(NULL, indexpos, PROT_READ, MAP_PRIVATE, indexfd, 0);
if (map == MAP_FAILED) {
perror("mmap");
@@ -1096,22 +1096,44 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
}
}
basezoom = MAX_ZOOM;
int z;
for (z = MAX_ZOOM; z >= 0; z--) {
if (tile[z].count > max[z].count) {
max[z] = tile[z];
}
if (max[z].count < 50000) {
basezoom = z;
}
// printf("%d/%u/%u %lld\n", z, max[z].x, max[z].y, max[z].count);
}
fprintf(stderr, "Choosing a base zoom of -B%d to keep %lld features in tile %d/%u/%u.\n", basezoom, max[basezoom].count, basezoom, max[basezoom].x, max[basezoom].y);
#define MAX_FEATURES 50000
if (basezoom < 0) {
basezoom = MAX_ZOOM;
for (z = MAX_ZOOM; z >= 0; z--) {
if (max[z].count < MAX_FEATURES) {
basezoom = z;
}
// printf("%d/%u/%u %lld\n", z, max[z].x, max[z].y, max[z].count);
}
fprintf(stderr, "Choosing a base zoom of -B%d to keep %lld features in tile %d/%u/%u.\n", basezoom, max[basezoom].count, basezoom, max[basezoom].x, max[basezoom].y);
}
if (droprate < 0) {
droprate = 1;
for (z = 0; z <= basezoom; z++) {
double interval = exp(log(droprate) * (basezoom - z));
if (max[z].count / interval >= MAX_FEATURES) {
interval = (long double) max[z].count / MAX_FEATURES;
droprate = exp(log(interval) / (basezoom - z));
interval = exp(log(droprate) * (basezoom - z));
fprintf(stderr, "Choosing a drop rate of -r%f to keep %f features in tile %d/%u/%u.\n", droprate, max[z].count / interval, z, max[z].x, max[z].y);
}
}
}
munmap(map, indexpos);
}
@@ -1375,7 +1397,11 @@ int main(int argc, char **argv) {
break;
case 'r':
droprate = atof(optarg);
if (strcmp(optarg, "g") == 0) {
droprate = -2;
} else {
droprate = atof(optarg);
}
break;
case 'b':